The numbers, available from the Office of Cyber Security (pdf) and Detica, claim an estimated loss of £9.2bn from IP theft - not illegal file-sharing but theft of trade secrets from UK firms.

A further £7.6bn is lost due to industrial espionage - defined as the theft of non-IP related data and £2.2bn is handed to criminal gangs by UK firms as the result of extortion. The OCS admits it has no evidence for such extortion, because it believes this crime is mostly not reported.

£1bn a year is lost due to loss or theft of customer data and £1.3bn goes thanks to direct online theft.

A spokesman for the Cabinet Office said it was impossible to say how much cyber crooks benefited from the billions they're extracting from Blighty.

The figures are based on a "most-likely scenario" but will form the basis of future policy.

The OCS warned: "Our assessments are, necessarily, based on assumptions and informed judgements rather than specific examples of cyber crime, or from data of a classified or commercially-sensitive origin."

It suggests approaching selected companies to ask if they are victims of cyber crime in order to both build awareness of the issues and to get some solid data on the problem.

The OCS also recommends the creation of a website to publicise the issue and to act as a central, anonymous, reporting hub for UK firms to report fraud.

The OCS estimates that the UK government loses £2.2bn due to cyber crime.

Even this number is an estimate. It is based on total tax and benefit fraud in the UK combined with an estimate of how many of these are due to "criminal attacks". The OCS treated all these attacks as cyber crimes "due in the main to the volume of transactions now conducted online".